Cleaning foreskin smegma when the foreskin wont go back?

i have mild phimosis and im doing stretching excercises. How do i know if the stretching excersises are working and is it ok to stretch the foreskin open and pour iodine benodine down inside to kill the smegma or decrease it on the head of the ?. and does smegma stop the foreskin from retracting someone please help